Clock alarm device settable to the minute



Feb. 8, 1955 H. JUNGHANS ETAL 2,701,439

CLOCK ALARM DEVICE SETTABLE TO THE MINUTE Filed Feb. 16, 1951 umllll United States Patent CLOCK ALARM DEVICE SETTABLE TO THE MINUTE Helmut .lunghans, Schramberg-Sulgen, and Adolf Kiiss, Schramberg, Germany, assignors to Gebruder Junghaus A. G., Schramberg, Gaisllalde, Germany Application February 16, 1951, Serial No. 211,306

6 Claims. (CI. 58-22) The present invention relates to chronometers with a release device, in particular alarm clocks. In alarm clocks of known design the time of waking can only be set with an accuracy of approximately 5 minutes. Moreover, with the usual 12-hour alarms the range of adjustment cannot be fully utilized, but only about /2 to 11 hours thereof; i. e. an alarm set for 7 oclock, for example, cannot, directly after running down, be set again immediately for the same time, but only for times which are at least about 1 to 1 /2 hours earlier, thus for 5:30 or 6 oclock at the latest. The reason for the imprecise and limited possibility of adjustment is the so-called alarm serving customarily to control the release member (alarm tension spring), and which rotates once in 12 hours and owing to its diameter which is limited for constructional reasons does not, in practice, permit of ensuring that the trip finger co-operating with the usual cam is tripped exactly to the minute and which, in addition, must be provided, for the purpose of returning the trip finger to the starting position, with a setting cam whose time 1elquivalent, in accordance with experience, is 1 to 1%.

ours.

These disadvantages of usual alarm clocks are known and already in themselves limit the possibilities of use thereof. In addition, however, there is also a need in the household for a chronometer capable of measuring short periods exactly to the minute, e. g. in baking, cooking, photographic work, listening to the radio, etc., and for these purposes the ordinary alarm clock cannot be used at all for the reasons stated. The present invention has as its object to produce an alarm clock which is exact to the minute and can beset, in practice, throughout the entire range of adjustment, by adding a small number of simple structural parts, while retaining to a considerable extent the proved forms of construction. 4

The basis of the solution of the problem of the invention is the idea of associating a fine release device with a pre-release device of a coarse nature in respect of time. According to the invention, it is intended to provide at least two control members connected behind one another in their action with reference to the release member, of which the one connected behind revolves at any given time at a considerably greater speed than the one in front. In the preferred embodiment of the invention for an alarm clock, the control member which rotates once in the time adjustment range (e. g. of 12 hours), has arranged after it a second control member which rotates at many times (e. g. 12 times) the angular velocity of the first control member, thus, in the case of the example, once an hour. Accordingly, when the first, slowly-running control member comes into operation, only a pre-release takes place and only when the more quickly-running second control member has also arrived in the release position does the main release take place; in other words, the hour hand and the minute hand are provided with corresponding release members. In principle, there would be nothing in the way, for example, of connecting another similar control member behind the minute control memberfor seconds control and, if required, similar ones for controlling fractions of a second. In addition, without departing from the idea of the invention, the range of adjustment could be extended from 12 to 24 hours.

The constructional embodiment of the idea of the invention preferably displays the following characteristics: The two control members may be arranged on a common axis, the slowly rotating control member being mounted on the more quickly-running one. Said more quickly- 2,701 ,439 Patented Feb. 8, 1955 running (minute) control member can be connected securely to a pinion, which engages with a gear of the usual dial train which rotates once an hour, while the (hour) control member which is mounted loosely on said pinion engages with a gear of the dial train which rotates once in 12 hours. Preferably, the common axis of the two control members is the alarm set spindle, upon which the setting members associated with the control members are arranged, the minute setting member being securely and the hour setting member loosely mounted, a gear ratio of 12:1 being adjusted between the two. For the purpose of setting the alarm, a pinion, which simultaneously carries the setting member, is fixedly mounted on the alarm set spindle and drives through a 12:1 reduction gear a toothed wheel which simultaneously carries the hour setting member, the setting members being constructed as so-called alarm cams of diiferent diameter and arranged inside one another and the hour cam being mounted on the setting pinion of the minute cam together with its toothed setting wheel. For indicating the alarm adjustment, there can be provided on the change speed gear co-operating with the two alarm cams a doublesided pinion, the outer half of which engages with a toothed wheel similar to the toothed setting wheel for the hour cam which is loosely mounted on the alarm set spindle and the hub of which carries the hour hand for the alarm setting dial, while the minute hand is fixedly mounted on the set spindle. For the purpose of facilitating adjustment exactly to the minute, a retaining disc graduated in minutes may be provided on the alarm set spindle and a retaining spring on the nearest plate of the mechanism, the retaining disc being conveniently constructed as a ratchet wheel in order to render it impossible to turn the alarm set spindle in the reverse direction.

Further characteristics and advantages of the invention may be seen from the following description of one example of embodiment, reference being made to the accompanying drawings wherein:

Figure 1 shows part of an alarm clock mechanism seen from the side, partly in section, the parts of the works not necessary for understanding the invention being omitted;

Figure 2 shows details of the control members; and

Figure 3 shows a front view of the arrangement of the dial plate.

In Figure l the front plate of the mechanism is indicated by 1; 2 is the rear plate of the mechanism, 3 one of the frame struts. The minute spindle 4 belongs to the clock movement (which is otherwise not shown in the drawing). 5 is the minute hand, 6 the hour hand, which is driven through the pinion 6a, change speed wheel 7, change speed pinion 8 and wheel 9 constituting the usual dial train.

The central spring wheel of the alarm mechanism is indicated by 10; it engages with the pinion 11 on the balance wheel spindle 12. 13 is the alarm balance wheel, 14 the alarm anchor and 15 the alarm anchor spindle, to which the alarm hammer 16 and the silencing arm 17 are secured.

The following parts serve to set and release the alarm. On the alarm set spindle 18, which can be turned by means of the knob 19 in the direction of the arrow 20, is mounted in loosely rotatable manner the pinion 21; it engages with the change speed wheel 7 and is hereinafter described as the minute control pinion 21. On the part 21 is mounted in loosely rotatable manner the toothed wheel 22, which engages with the change speed pinion t and is hereinafter described as the hour control wheel 22. The minute control pinion 21 carries the minute control finger 21a and the hour control wheel 22 the hour control finger 22a.

Opposite the minute control finger 21a and the hour control finger 22a are located the minute alarm cam 23 and the hour alarm cam 24 respectively. The minute alarm cam 23 is fixedly connected to the pinion 25 and this in its turn is fixedly mounted on the alarm set spindle 18; the pinion 25 is hereinafter described as the minute setting pinion.

On a projection 25a on the minute setting pinion 25 there is mounted in loosely rotatable manner the toothed wheel 26; this carries the hour alarm cam 24 and is hereinafter described as the toothed hour setting wheel.

The co-operation of the trip finger with the alarm snail may be predetermined as is known and it is therefore sufficient to remark briefly here that the minute control pinion 21 with the minute control finger 21a and thehour control wheel 22 with the finger 22a mounted on the part 21 can be moved in the direction of the double arrow 27 on the alarm set spindle 18 and, in fact (in Figures 1 and 2 of the drawing) is moved to the right, when the control fingers 21a and 22a are able to fall down on the sloping edges 23a and 24a of the two alarm cams. This movement takes place under the action of the alarm tension spring 28, the locking nose 28a of which releases the silencing arm 17 ,on the alarm anchor spindle at the same time and allows the alarm arrangement to come into operation.

The minute setting pinion 25 keyed on the alarm set spindle and the hour setting wheel 26 loosely running on the former are located above the change speed gear consisting of the wheel 29 and the pinion 30 in a working relationship which is such that one revolution of the hour setting wheel is equivalent to 12 revolutions of the minute setting pinion. The minute setting pinion 25 therefore has the same number of teeth as the minute control pinion 21 and the hour setting wheel 26 the same number of teeth as the hour control wheel 22; in the same way, the change speed gear 29-30 has the same number of teeth as the change wheel gear 7-8. Both change gears are mounted rotatably, independent of each other, on the common axis 31.

The arrangement of the control members and the arrangement of the setting members has been described and the arrangement of the members indicating the setting of the alarm at any given time still remains to be described. As the alarm set spindle 18 is fixedly connected to the minute setting pinion, it is suitable as a member for the minute setting hand 32. This is fixed at the front end of the spindle. The hour setting hand 33 must revolve in the ratio of 12:1 and is therefore again driven through a change speed gear. In fact, the change speed gear 2930 is used for the purpose, the change speed gear pinion 30 being compound gear and having an outer portion 30a. The alarm hour hand wheel 34 now engages with outer portion 30a of the change speed gear pinion; on the tube 35 is mounted the hour setting hand 33. The alarm hour hand wheel 34 has the same number of teeth as the hour setting wheel 26 and the hour control wheel 22.

The method of operation of the arrangement is as follows:

Setting of alarm By means of the knob 19, the alarm set spindle 18 is turned in the direction of the arrow 20, while observing the alarm setting dial plate 36 (Fig. 3), until the setting hands 32 and 33 (which run anti-clockwise) are at the desired time of waking. During this operation, setting pinion 25 which is fixedly connected to the alarm set spindle 18 and, moreover, carries the minute cam 23 has driven the hour setting wheel 26 with the hour cam 24 through the change speed gear 29--30, so that at the end of the setting operation the sloping edges 23a and 24a are in the predetermined position with respect to the control fingers 21a and 22a. At the same time, the alarm set spindle 18 has carried with it the minute setting hand 32 which is fixedly connected to it and the hour setting hand 33 has been moved by the pinion 25 through the change speed gear 2930a and the alarm hour hand wheel 34.

Release of alarm As the clockwork unwinds, the minute spindle 4 drives, through the pinion 6a, the change speed gear 78 and through the latter the minute control pinion 21 and the hour control wheel 22; at the same time, the minute control finger 21a slides on the minute cam 23 and the hour control finger 22a on the hour cam 24. As the minute cam 23 revolves twelve times faster than the hour cam 24, the minute control finger 21a will, as a rule, run past the sloping edge 23a of the minute cam 23 several times without being able to fall, because the minute control pinion 21 is prevented, through the hour control wheel 22 by the hour control finger 2211, which cannot yet fall on to its control 24, from being moved (Figs. 1 and 2 of the drawing) to the right. As the clock movement continues to unwind, the time will now arrive when the time of waking is reached. The hour control finger 22a will then reach the hour cam 24 by way of the sloping edge 24a and now be located over a notch 24b, whose time equivalent is at least one hour. Within this period a further revolution of the minute cam 23 may thus be carried out, i. e. only a part revolution, corresponding to the number of minutes set, will take place. When the minute control finger 21a now arrives at the sloping edge 23a of the minute cam, it can fall this time, because the hour control finger 22a is over the notch 24b onthe hour can}: 24 and is not prevented from being moved to the rig t.

The alarm tension spring 28 can therefore now move the minute control pinion 21 together with the wheel and both control fingers to the right and thereby release the alarm anchor spindle 15 through the nose 28a and the silencing arm 17.

Some time after the fall has taken place, the minute control finger 21a strikes against the lifting curve 23b of the minute cam and is returned by the latter into the locked position while the minute control pinion 21 and the hour control wheel 22 with finger 22a mounted thereon are moved. This return movement takes place against the action of the alarm tension spring 28, which, at the same time, comes within the range of the silencing arm 17 on the alarm hammer spindle 15 with its locking nose 28a. The time value of the lifting curve on the minute cam is approximately 10 minutes, i. e. only this amount is deducted from the range of adjustment of the alarm clock and immediately after release has taken place it can be set for a waking time which is 10 minutes before the position of the clock at the moment. Since the minute cam revolves at twelve times the angular velocity of the hour cam it is clear that the accuracy of release can be considerably increased, in spite of the fact that the minute cam encircles the hour cam. The subdivision of the control member according to the invention would naturally correspond to the extension of the effective edge of the hour cam to 12 times its length, a step which cannot, as a rule, be taken for constructional reasons.

In order to facilitate adjustment exactly to the minute, a ratchet wheel 37 with 60 teeth, which co-operates with the pawl 38, is fixed on the alarm set spindle, the pawl simultaneously preventing the rotation of the alarm set spindle 18 in the reverse direction against the arrow 20, because otherwise the minute control finger 21a when in the fallen position would strike against the sloping edge 23a and could be damaged.

The release device described is preferably intended for alarm clocks, but may also, without departing from the scope of the invention, be employed in other chronometers, in time switches and in clock movements for technical purposes.

We claim:

1. In an alarm clock having a movement including the usual 12:1 reduction dial train and an alarm mechanism, an alarm device settable to the minute comprising a setting spindle, a flanged pinion journalled for rotation on the setting spindle, a trip member fixed to the flanged pinion, a gear wheel rotatably mounted on the flanged pinion, a second trip member fixed to the gear wheel, the setting spindle being positionally related to an intermediate compound gear of the dial train to enable meshing therewith of the flanged pinion and the gear wheel to be rotated thereby in the ratio 12:1, and means engageable with the trip members in set positions to release the alarm mechanism.

2. In an alarm clock settable to the minute, a dial train comprising a centershaft carrying a centershaftpinion and the minute hand, a cannon carrying the hour wheel and the hour hand, an intermediate compound gear composed of an intermediate gear pinion and an intermediate gear wheel interconnecting the centershaft pinion and the hour wheel, an alarm setting spindle, a rotary pinion journalled on the said setting spindle meshing with the intermediate gear wheel and having the same num' ber of teeth as the centershaft pinion, a gear wheel rotatably mounted on the setting spindle with respect to the setting spindle and to the rotary pinion journalled by the setting spindle, said gear wheel meshing with the intermediate gear pinion and having the same number of teeth as the hour wheel, two alarm trip members rotatably mounted on the setting spindle, one of said members fixed to the rotary pinion and the other fixed to the gear wheel mounted on the setting spindle, and means responsive to movement of said trip members for diseiigaging a spring-member provided for stopping the a arm.

3. In an alarm clock settable to the minute, a dial train comprising a centershaft carrying a centershaft-pinion and the minute hand, a cannon carrying the hour wheel and the hour hand, an intermediate compound gear composed of an intermediate gear pinion and intermediate gear wheel interconnecting the center-shaft pinion and the hourwheel, an alarm setting spindle, a rotary and shiftable flanged pinion journalled on the said setting spindle, said flanged pinion meshing with the intermediate gear wheel and having the same number of teeth as the centershaft pinion, a gear wheel rotatably mounted on the flange of the said rotary and shiftable flanged pinion, said gear wheel meshing with the intermediate gear pinion and having the same number of teeth as the hour wheel, two alarm trip members mounted on the setting spindle, one of said members fixed to the rotary and slidable flanged pinion and the other to the rotary gear wheel carried by the flange thereof, a spring member for stopping the alarm, and means engageable with said trip members to cause shifting of the flanged rotary pinion, thereby to move said spring member into releasing position.

4. In an alarm clock as in claim 3, and including a 12:1 reduction gear having two end pinions and an intermediate gear wheel, a flange extending from the pinion fixed to the spindle, a pinion fixed to the setting spindle and carrying the means engageable with said trip member carried by the rotary pinion journalled on the setting spindle. a first rotary gear wheel journalled on the flange of the pinion fixed to the setting spindle and carrying the means engageable with the trip member carried by the gear wheel meshing with the intermediate compound gear, the trip members and the means engageable therewith comprising respectively trip fingers and tripping cams, one of the two flanged pinions being mounted to slide towards the other on the spindle, a cannon carrying the hour hand of the alarm setting device and a second gear wheel rotatable with the cannon being rotatably mounted on the setting spindle, the pinion fixedly mounted on the setting spindle meshing with the intermediate gear wheel of the 12:1 reduction gear and the first and second gear wheels meshing each with one of the .pinions associated on each side of the said intermediate gear wheel, and a minute hand fixed on the end of the setting spindle.

5. An alarm clock as in claim 3 wherein the trip members comprise radially spaced trip fingers and the means engageable therewith comprise coaxial tripping cams substantially arranged in a common plane.

6. An alarm clock as in claim 3 further comprising a ratchet wheel fixed on the spindle and a fixed spring pawl engaging the ratchet wheel and allowing the setting spindle to be turned in one direction only, the number of teeth of the ratchet wheel corresponding to an adjustment of the time setting spindle within 1 minute accuracy.

Lutterell et a1 Oct. 14, 1924 Dunn Oct. 15, 1929 

